1. Field of the Invention
The invention relates generally to hydraulic rotary vane pumps and more specifically to a hydraulic rotary vane pump assembly having an integrally mounted drive motor and rotary vane pump.
2. Description of Related Art
In order to improve the operation and efficiency of power steering systems utilizing pressurized hydraulic fluid a current design approach utilizes a hydraulic rotary vane pump directly driven by a variable speed electric motor. Such electro-hydraulic power steering systems (EHPAS) provide improved steering feel, sensitivity, control and reduced energy consumption.
The packaging of such devices, i.e., a dedicated electric motor and hydraulic rotary vane pump, has yet to reach a level of sophistication commensurate with other components of the system. That is, present designs, simply comprehend a cartridge type rotary vane pump mounted upon appropriate stationary vehicle components and an adjacent and operatively associated electric motor similarly secured. In this configuration the pump has its own housing, the motor has its own housing, a coupler for the pump and motor shafts is required and various brackets and fasteners for mounting the pump and motor are required.
Clearly a motor and pump assembly of this type does not represent an efficient package from weight, space and cost standpoints. The current invention relates to an improvement in such assemblies wherein reduced weight and manufacturing simplicity are two of the many benefits enjoyed.
An integrated, i.e. unitary, rotary hydraulic vane pump assembly reduces cost and simplifies manufacturing thereof. The integrated assembly includes an electric motor, a rotary vane pump, a pump housing and an end bell. The end bell has an inlet fitting or passageway which communicates with the inlet of the rotary vane pump. The pump housing receives the vane pump and is received within the end bell. The electric motor is secured to the face of the pump housing opposite the end bell. The pump housing includes outlet passageways and a centrally disposed axial opening for receiving an output shaft of the electric motor. The rotary vane pump includes end sections and a center, cam ring section which receives a vane rotor assembly coupled to the output shaft.
Thus it is an object of the present invention to provide an integrated, i.e. unitary, rotary vane pump and motor assembly.
It is a further object of the present invention to provide an integrated hydraulic rotary vane pump and motor assembly having common components and features which reduce weight and simplify manufacturing.
It is a still further object of the present invention to provide an integrated rotary hydraulic vane pump assembly disposed within a housing to which an electric drive motor is attached.
Further objects and advantages of the present invention will become apparent by reference to the following description of the preferred embodiment and appended drawings wherein like reference numbers refer to the same component, element or feature.